Most people wouldn't want that "problem" fixed. But here's my thought. You might be able to rough up one of the hinge pins so that it binds slightly, thereby leaving the door where you put it. Hopefull, it won't squeak so loudly that it becomes a bother.

My daughter prefers to leave the door partway open, but it just swings all the way open. As near as I can tell with the levels that I have, it's not aligned wrong. It just keeps going once it's unlatched. I know that doors can stay part way open since every other door in the house will do that.

If you want to take the time to experiment, I suggest putting a thin shim under the frame side of the top hinge. If that makes it better or worse, go from there. Shim the other hinges (or the door side of the hinge) as necessary to get the desired result.

What this post needs is a LEVEL..........to accurately fix your door you need to determine where it is out of plumb.........

Set the level on the edge of the door and check for plumb(vertical) in both the open and nearly closed position........a door that always swings will be out in at least one direction............Understanding/Seeing what's wrong is the hardest part............

Now either shim the "low" hinge or chisel the mortise in the frame for the "high" hinge to correct the problem............

Before attempting any of these adjustments make sure all the hinge screws are tight in both the door and the frame............